This invention relates to a flotation system for a buoy and, more particularly, to the releasing of a compressed fluid from a container of such fluid for deployment of a float.
Buoys are frequently deployed on the surface of a body of water, such as the ocean, for identifying locations thereon and, in the case of sonobuoys, for receiving sonic signals which may be generated within the water. For example, sonobuoys may be dropped from aircraft, the sonbuoys containing flotation which is activated upon contact of the sonobuoy with the water for deployment of a float from which the sonobuoy is suspended at a predetermined distance below the surface of the water.
A flotation system which is in common use employs a container of a compressed fluid, such as carbon dioxide gas, in combination with a squib-firing circuit which employs an explosive charge for puncturing the container to release the compressed fluid. A battery, responsive to the salt water of the ocean, provides an electric current for activating the squib when the sonobuoy contacts the surface of the ocean.
A problem has arisen in the aforementioned puncturing of the container in that the resulting punctured region of the container provides a relatively small cross-section through which the escaping fluid must pass enroute to the float. As a result, the compressed fluid, which may comprise both liquid and gaseous carbon dioxide within the container, is cooled by the gas escaping through the constriction of the orifice at the point of puncture. Since a cooling of a fluid reduces the vapor pressure thereof, the rate of delivery of the gas to the float steadily diminishes with the result that the float may not have as much buoyancy as would be desired during the initial stages of the deployment of the float. As a result, reliable flotation may require an unduly large container of compressed fluid such that a sufficient amount of gas is released to the float before extensive cooling occurs to the fluid within the container. In many situations for the deployment of buoys, the physical size of the buoy is limited to a predetermined size so that the use of an unduly large container undesirably reduces the space available for other equipment within the buoy such as a sonar receiver and/or sonar transmitter.